1. Field of the Invention
This invention relates to surgery and more particularly to a method and an apparatus for identifying a proper tibia bone rotation relative to the femur bone in a knee replacement surgery.
2. Description of the Related Art
One of the most difficult measurements to be determined in a knee replacement surgery is the identification of the rotational angle of the tibia bone relative to the femur bone. Various types of measurements have been suggested by the prior art to determine the proper angular rotation between the tibia bone relative to the femur bone. Many computer programs have been developed to assist in the identification of the rotational angle of the tibia bone relative to the femur bone. The following United States Patents are representative of computer programs developed for orthopedic surgery.
U.S. Pat. No. 6,385,475 to Cinquin, et al discloses a process for the preoperative determination of the positioning data of endoprosthetic parts of a central joint relative to the bones forming the central joint, a respective outer articular point is determined by way of movement of the bones about a respective outer joint which is located at the end of the two bones facing away from the central joint. An articular point is determined for each of the two bones in the area of the central joint, and a direction characteristic for each of these bones is determined by way of a straight-line connection of the two articular points obtained in this manner for the two bones. The orientation of the endoprosthetic parts relative to this characteristic direction is then determined. Apparatus for carrying out the process is also provided.
U.S. Pat. No. 6,514,259 to Picard, et al, discloses a plate probe and associated system and method for facilitating the orientation of an osteotomy and the implantation of an artificial joint component during arthroplastic surgery requiring an osteotomy. The probe comprises a coupler and a plate. The coupler is configured so that it can be connected to a position tracker, such that the position and orientation of the plate can be determined from the position of the tracker. The plate is configured so that it can be inserted into an opening of a bone-cutting mechanical guide, which is generally designed for receiving and guiding a surgical saw blade during a cutting operation.
U.S. Pat. No. 6,692,447 to Picard discloses a system for determining pivot centers for proximal and intermediary articulations of an appendicular skeleton. The system includes a single marker affixed to a bone, the marker having a signal transmitter; a sequence involving at least one movement for moving a portion of the appendicular skeleton; a signal receiver for collecting data points correlating to the position and orientation of the marker; at least one processing device for selecting a number of skeletal positions during, the sequence using the collected data points; and for assigning a value to each posture representing the position and orientation of the marker in a predetermined point of reference, and an algorithm for determining the coordinates of the rotational centers of the proximal and intermediary articulations using the assigned values.
U.S. Pat. No. 6,915,150 to Cinquin, et al. discloses a process for the preoperative determination of the positioning data of endoprosthetic parts of a central joint relative to the bones forming the central joint, a respective outer articular point is determined by way of movement of the bones about a respective outer joint which is located at the end of the two bones facing away from the central joint. An articular point is determined for each of the two bones in the area of the central joint, and a direction characteristic for each of these bones is determined by way of a straight-line connection of the two articular points obtained in this manner for the two bones. The orientation of the endoprosthetic parts relative to this characteristic direction is then determined. Apparatus for carrying out the process is also provided.
U.S. Pat. No. 7,033,360 to Cinquin, et al. discloses a process for the preoperative determination of the positioning data of endoprosthetic parts of a central joint relative to the bones forming the central joint, a respective outer articular point is determined by way or movement of the bones about a respective outer joint which is located at the end of the two bones facing away from the central joint. An articular point is determined for each of the two bones in the area of the central joint, and a direction characteristic for each of these bones is determined by way of a straight-line connection of the two articular points obtained in this manner for the two bones. The orientation of the endoprosthetic parts relative to this characteristic direction is then determined. Apparatus for carrying out the process is also provided.
Although many computer programs have been developed to assist in the identification of the rotational angle of the tibia bone relative to the femur bone, the identification of the proper rotational angle of the tibia bone still eludes the medical art.
Identification of tibia rotation in a knee replacement is very difficult. Some surgeons rely on relation to tibia tuberosity that proved to be unreliable. Other surgeons rely on tibia rotation established by previous knee replacement surgeons and that proved to be unreliable. Presently, there is no scientific accurate way of identifying the knee tibia rotation in knee surgery.
The reason is the tibia has a wide range of rotation especially after transecting the proximal 10 mm or so as a routine step in knee replacement. It is difficult to choose the right spot on the tibia and consider that to be the ideal tibia rotation.
Therefore, it is an object of the present invention to provide a method for determining the proper rotational angle between a tibia bone relative to a femur bone in a knee replacement surgery.
Another object of the invention is to provide a method for determining the proper rotational angle between a tibia, bone relative to a femur bone which is determined by the physical properties of the patient.
Another object of the invention is to provide a method for determining the proper rotational angle between a tibia bone relative to a femur bone which is determined by an external rotation of the tibia in extension and an internal rotation of the tibia flexion.
Another object of the invention is to provide an apparatus for determining the proper rotational angle between a tibia bone relative to a femur bone comprising computer hardware and computer software incorporating the present method.
The foregoing has outlined some of the more pertinent objects of the present invention. These objects should be construed as being merely illustrative of some of the more prominent features and applications of the invention. Many other beneficial results can be obtained by applying the disclosed invention in a different manner or modifying the invention with in the scope of the invention. Accordingly other objects in a full understanding of the invention may be had by referring to the summary of the invention and the detailed description describing the preferred embodiment of the invention.